Purpose The aim of this study is to evaluate the efficacy of topical cysteamine 0.55% eye drops in the treatment of corneal cystine crystal deposits in patients with nephropathic cystinosis.
Methods Thirty-two patients with nephropathic cystinosis were prospectively included in the study. Patients with corneal cystinosis were treated with topical cysteamine 0.55% eye drops. They were examined before treatment, on each monthly visit and after treatment at the last follow-up. Photophobia was classified as grade 0 (none) for no photophobia, grade 1 (mild) for photophobia in bright light, grade 2 (moderate) for photophobia in room light and grade 3 (severe) for photophobia in dim light. Corneal cystine crystals were graded as grade 0=none, grade 1=1–10 crystals/mm2, grade 2=11–50 crystals/mm2, grade 3=more than 50 crystals/mm2. The main outcome measure was evaluation of photophobia and resolution of corneal cystine crystals.
Results There were 13 male and 19 female patients. The mean age was 8 years with an age range of 8 months to 19 years. The mean follow-up period was 4.1 years with a range of 2–8 years. Improvement of photophobia was not clinically significant in symptomatic patients. Patients displayed statistically significant worsening of corneal cystine deposits during the follow-up period.
Conclusions This study has shown that topical 0.55% cysteamine eye drops may have limited effects in decreasing the corneal cystine deposits in patients with severe forms of nephropathic cystinosis.
Trial registration number NCT02766855, Results.
- Treatment Medical
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Competing interests None declared.
Ethics approval The Protocol was approved by the Institution Review Board (IRB) of King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia and The Eye Center, Riyadh, Saudi Arabia. The study design complied with the standards set forth by the Declaration of Helsinki and was registered at clinicaltrials.gov (registration number is NCT02766855).
Provenance and peer review Not commissioned; externally peer reviewed.